In order to improve the seismic resistance of the baem-to-column joint, the authers have studied the welding procedures that can reduce the stress concentration induced by steel backing and scallop toe,maintaining the merits of the on-site welding without bracket.Consequently,it has been found that the seismic resistance of the joint can be improved by employing the backing-less process that replaces the steel backing with the overhead MAG weld made using a special flux-cored wire and by applying the reinforcement buildup welding at the scallop toe by MAG welding with a conventional solid wire.